* On Thu, Oct 27, 2005 at 01:04 PM (+0100), Jonathan Brooks wrote:
I have an AMD Athlon64 X2 machine running SuSE 10 (x86_64) on an Nvidia Nforce4 Ultra motherboard, and have noticed that the system clock has become unstable (it runs too fast). Not sure when it occurred, but I have been getting a lot of error messages like this in dmesg:
warning: many lost ticks. Your time source seems to be instable or some driver is hogging interupts rip acpi_processor_idle+0x12f/0x37f [processor]
I had a very similar (or the same?) problem on a "Tyan Thunder K8SE 2892G3NR" dual Opteron machine running SuSE Linux 9.3: The system time ran much too fast (minutes were almost running like seconds), the screen saver started only seconds after not moving the mouse or pressing a key and the log file was full of these messages ("many lost ticks").
My notice was that it especially happend when the CPU usage grew, so I suppose it was related to the "powernow" feature of the CPU, because at least on Opteron systems SuSE's "power management" changes the CPU clock based on the load.
After I upgraded to the most recent vanilla kernel the problem was gone.
The powernow-k8 driver in SL9.3 caused clock instability on SMP machines that did not support HPET timers; SL10.0 and the mainstream kernel support PMTimer for those machines. That's most likely what you were seeing. The single processor, dual-core problem is believed to be something different and is under investigation at AMD. We will make a statement as soon as we have definite information. -Mark Langsdorf AMD, Inc.